Spark plug



May 13, 1924. 1,493,800

W. J. BLIFFERT SPARK PLUG Filed April 9, 1923 Patented May 13, 1924.

WALTER J'. BLIFF'ERI, OF MILWAUKEE, WISCONSIN".

SPARK PLUG.

Application filed April 9, 1923. Serial No. 630,945.

To all whom it may concern:

Be it known that I, WALTER J. BLIFFERT, a citizen of the United States, and resident of lviilwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Spark Plugs; and I do hereby declare that the following is a. full, clear, and exact description thereof.

This invention relates to spark plugs and is particularly directed to a vented spark plug.

Vented spark plugs as heretofore constructed have not proven wholly satisfactory for the reason that additional fittings and elaborate constructions were necessary to accomplish the venting of the plug. In addition to this, the expense in manufacturing these devices precluded the cheap price necessary to the commercial exploitation of these devices, for it was found necessary to perform. a relatively large number of 0porations in the production of these plugs.

A further defect lay in the fact that difficulty was experienced in securing a tight seating of the valve mechanism associated with the plug, with consequent leakage and loss of power.

This invention is designed to overcome the above noted defects, and objects of such invention are, therefore, to provide a vented spark plug in which no extra valve fittings are used, to provide a vented spark plug in which a poppet valve is employed, to provide a vented spark plug in which the poppet valve seats directly upon the casing of the plug, to provide simple and effective means for priming in connection with the vented plug, and to provide means for automatically varying the tension exerted upon the poppet valve in accordance with the throttling of the engine.

An embodiment of the invention is shown in the accompanying drawings in which:

The single figure is a vertical sectiona view through the spark plug.

The spark plug comprises an outer casing 1 adapted to be screwed into the engine cylinder and carrying an angular electrode .2 adjacent its lower end. Vithin this easing the porcelain member 3 is position, such member carrying the central electrode 4c and having a cylindrical portion 5 spaced from the inner walls of the casing 1 in the usual manner. Any desired means may be employed to retain the porcelain member in position, such as the gland nut 6. The casingl is provided with a radial aperture 7 within which the poppet valve stem 8 1s position. This stem 8 is of less diameter than the diameter of the aperture 7 as may be seen from the drawings. The poppet valve is provided with an enlarged head 9 which is bevelled and seats upon a correspondingly bevelled surface. or flared con tinuation of the aperture 7, which c0nstitutes therefore, a poppet valve seat. The spindle or stem. 8 of the poppet valve is loosely surrounded by helical spring 10 which bears at one end against the casing l and at its other end against a washer 11 positioned upon the stem 8 held against a pin or other stop. To the outer end of the poppet valve spindle one end of a spring 12is connected, the other end of the spring 12 being connected to a cable 13.

It is a well known fact that the vented spark plugs work best. during full load and are relatively inefficient and frequently detrimental to the effective operation of the engine when the engine is throttled down to a low point.

Provision has been made in this spark plug for altering its action at diiferent degrees of throttling. This is secured by connecting the cable 13. with the manual or automatic mechanism for throttling, so that when the engine is throttled down, tension is exerted upon the cable 13 consequently increasing the tension upon the spring 12. The parts are so adjusted that when the engine is throttled down to low value, the poppet valve will not open as it is held to its seat by an increased spring force as described. It is obviously within the scope of this invention to provide additional manual means for operating the cable 13, so that the spring 12 may be tensioned as desired.

In order to provide for the ready priming of the engine, particularly when starting under difiicult conditions, a relatively small cup 14 is provided in an integral outwardly projecting lip from the casing l, and immediately adjacent the aperture 7 This cup is adapted to be filled with any priming fuel such as the readily volatilized ether for instance.

In constructing the spark plug, the casing 1 is first bored as desired and provided-with the aperture 7 and valve seat. Thereafter,

the valve is slipped into the main bore of the casing 1, and its stem 8 inserted within the aperture 7. The spring 10 and Washer 11 are, thereafter, positioned, and subsequent ly the porcelain member 3 is secured in place.

It will be seen that an extremely simple vented spark plug has been provided which may be made in a very cheap manner without recourse to elaborate machine shop operations in its production;

It will further be seen that auxiliary fittings or. elaborate constructions have been wholly avoided, and that the spark plug may be produced at an extremely small cost.

It will further be seen that the detrimental action of the spark plug, at relatively low rates of speed, of the engine when it is throttled down, is prevented by automatically increasing the tension of the valve seating springs.

It is to be noted in this connection that all of the advantages of the vented spark plug constructions have been retained, and in addition thereto, an automatic altering of the characteristics of the vented spark plug has been added together with a simpler construction, and one more cheaply produced.

I claim:

1. A vented spark plug comprising a casing, an insulating member spaced from a portion of the inner walls thereof and carrying an electrode,said casing having aradially extending aperture opening into the space between said insulating member and said casing,said aperture having an inner bevelled surface providing a valve seat, a poppet valve having a stem loosely positioned within said aperture, and having a bevelled enlarged head cooperating with said seat, a spring for urging said valve toward said seating position, and a second spring connected to said stem at one end, and adapted to be connected to the throttle mechanism, whereby the tension of said second spring is increased as the throttle is increased. 4

2. A vented spark plug comprising a casing having a radial aperture therethrough,

the county of Milwaukee and State of Wisconsin.

WALTER J. BLIFFERT. 

